Coriolus versicolor, also known as Agaricus versicolor, Boletus versicolor, Polyporus versicolor, Polystictus versicolor, Poria versicolor, Trametes versicolor, Yun-Zhi (Chinese), Kawaratake (Japanese), and “turkey tail” (North America), belongs to the Basidiomycetes class and Polyporaccae family. It is widely distributed throughout the world, where more than 120 different strains have been identified in the wooded temperate zones of Asia, Europe, and North America.
The medicinal value of C. versicolor was first recorded in Compendium of Materia Medica (Compendium Medica) by Li Shi Zhen during the Ming Dynasty (1368-1644AD) in China. According to Compendium Medica, C. versicolor (Yun-Zhi), if consumed regularly, can invigorate vital energy, maintain one's optimal weight, promote longevity, and avoid unnecessary aging. C. versicolor is also believed to have protective effects on liver and spleen function (3), and has been used in the treatment of a variety of symptoms associated with liver dysfunction and respiratory tract infection. In China and Japan, C. versicolor is dried, ground, and made into tea. C. versicolor has not been reported to have toxic effects in long-term uses (24).
It is reported that C. versicolor has immunomodulatory (4), anti-tumor (4), antimicrobial (5) and antiviral effects (6, 7). These pharmacological effects may be largely produced by polysaccharide-peptides (PSP) such as polysaccharide Krestin (PSK) (4).
Specifically, C. versicolor is reported to strengthen the immune system that defends against pathogens and diseases. In vitro experiments revealed that aqueous extracts of C. versicolor effectively activated immune cells, including T lymphocytes (8-14), B lymphocytes (9, 13), monocytes/macrophages (9, 12, 13, 15), bone marrow cells (13), natural killer cells, and lymphocyte-activated killer cells (8, 9). In addition, it is reported that C. versicolor extracts enhance the production of antibodies and various cytokines, including interleukins such as IL-2 and IL-6, interferons, and tumor necrotic factors (9). In vivo studies also demonstrated that aqueous C. versicolor extracts help to restore immune responses in patients who received chemotherapy (5, 14, 16, 17) and help to reduce immuno-suppression caused by anticancer drugs.
In addition, C. versicolor can inhibit the growth, migration and metastasis of tumor cells (18). Studies have shown that a C. versicolor extract inhibits the growth of cancer cells in vitro, including gastric cancer cells (e.g., 7907), lung cancer cells (e.g., SPC), leukemia cells (e.g., MCL), lymphoma cells (e.g., SLY), human leukemia cells (e.g., HK-60), liver cancer cells (e.g., SMMU-7721), and stomach cancer cells (e.g., SCG-7901) (16, 19-23). The extract may also be used for prophylaxis against esophageal, colon, breast, liver, lung, and bladder cancers (9). While the C. versicolor extract exhibits potent anti-tumor activity, it has little cytotoxic effects on normal cells (25).
While C. versicolor has a long history of empiric uses, there is still limited knowledge about the precise mechanism by which it exerts its pharmacological action. In addition, many biologically-active chemical constituents of C. versicolor have not been identified. Thus, a need exists for elucidating the drug mechanism of C. versicolor, as a means through which novel therapeutic compositions and methods can be developed. In addition, a need exists for the development of more efficient and convenient extraction protocols for scaling-up the production of C. versicolor extracts and for the identification of its biologically-active chemical constituents for therapeutic uses.